Miniaturization is a development tendency of modern analytical science and technology because for biotech and pharmaceutical industry it means not only to use less limited samples, precious chemical compounds and expensive reagents, but also to increase sensitivity and to reduce incubation time for some types of assay relaying on the ratio of volume to surface area of the reaction well or tube, such as Enzyme Linked Immunosorbent Assay (ELISA). But a miniaturized analytical system that uses a micro-well plate will arise difficulties and problems for quantitative liquid transfer into or from a tiny well even with automations. The existing liquid handling techniques of pipetting, piezoelectric droplet dispensing, split pin dispensing, and microspritzing can easily cause contamination of neighboring wells and loss of sample volume resulting from substantial splashing and entrapment of air bubbles.
High throughput screening assays and techniques of various types are largely used for the discovery and development of new therapeutic agents by companies from small biotech to international pharmaceutical giants. These assays are often carried out at a reduced volume in multi-well plates in order to reduce the cost and save valuable samples. Currently the 96-, 384-, or 1536-well format multi-well plates are principally used in high throughput screening assays. Because a number of pipetting steps are involved in the assay procedure, manually performing high throughput assay in the 96-well format is already very tedious and can easily introduce manmade pipetting mistakes. Although automated assay systems may enable to increase the high-throughput screening capacity of a wide variety of biochemical and molecular biology tests such as enzymatic activity, receptor binding, macromolecular interactions, protein expression, and protein folding and assembly, but the extremely expensive robotic systems may not be affordable for small biotech companies and is not worthwhile to buy even for big pharmaceutical companies to carry out only limited screens. So far, there is no dramatic progress for miniaturized assays needing separation steps like ELISA.
Multiplexed detection technique is also a trend of the modern analytic techniques, which allows simultaneously detecting various analytes from one single sample. This technique is particular useful for diagnosis, clinical study and pathway identification. Although protein micro-array technology can meet the multiplexed detection requirement, some technical difficulties still exist. For example, it is not designed for high throughput and manual performance. The reaction conditions for all analytes are the same. Furthermore, the extremely high cost for the automation and the protein chip will be an insurmountable barrier for it being widely used.
On the eve of worldwide outbreak of bird flu, it urgently needs a cost-effective, easy-to-use, robust, rapid, and high throughput micro-assay system capably to test an enormous amount of samples by assays like ELISA in order to monitor, prevent and control the epidemic situation. Hospital, biotech and pharmaceutical industry, academic institute and university, agriculture, food and beverage industry also welcome such a technology.